Digital Foundry Article Technical Discussion Archive [2016 - 2017]

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note havent error checked or anything (works on chroome/firefox though some errors which I cant be bothered fixing as this wasnt really for sticking on the web, but you can alter the length of branches etc with the sliders)
http://zedzeek.com/webgames/Qualitree/
Also its not reallyrelated to what I'm talking about WRT grass and using actual geometry

I am talking about alpha masking single ferns/plants/flowers/grass blades
Yes for ferns etc alpha polygons are gonna give better response as the polygon etc count to approx model this with geometry is gonna be far too high, but for long grass eg the battlefield 2 screenshot you posted above (2nd pic) it will look far better,
the thing is with that is, look at those edges, alphatest looks like ;), not good, but thats not the main issue with it, the issue is it looks OK in a static screenshot but if you're actually playing the game with the camera or grass moving the whole thing just falls flat, like you're looking at lots of quads with grass textures painting on them
check out my grass here again
you actually feeling like the grass is a solid object that exists in the world
 
Doom's Vulkan patch is a PC performance game-changer
Digital Foundry tests the update and talks tech with id software.

id Software itself is pretty clear about the advantages of Vulkan and async compute. We asked the team whether they see a time when async compute will be a major factor in all engines across platforms.

"The time is now, really. Doom is already a clear example where async compute, when used properly, can make drastic enhancements to the performance and look of a game," reckons KHAAAAAAAAN! "Going forward, compute and async compute will be even more extensively used for idTech6. It is almost certain that more developers will take advantage of compute and async compute as they discover how to effectively use it in their games."
 
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Tech Interview: Doom

Very nice interview, probably one of the very best DF articles in a while :)

On async compute:
Digital Foundry: Can you go into depth on the wins asynchronous compute gave you on the consoles and any differential there between PS4 and Xbox One?

Jean Geffroy: When looking at GPU performance, something that becomes quite obvious right away is that some rendering passes barely use compute units. Shadow map rendering, as an example, is typically bottlenecked by fixed pipeline processing (eg rasterization) and memory bandwidth rather than raw compute performance. This means that when rendering your shadow maps, if nothing is running in parallel, you're effectively wasting a lot of GPU processing power.

Even geometry passes with more intensive shading computations will potentially not be able to consistently max out the compute units for numerous reasons related to the internal graphics pipeline. Whenever this occurs, async compute shaders can leverage those unused compute units for other tasks. This is the approach we took with Doom. Our post-processing and tone-mapping for instance run in parallel with a significant part of the graphics work. This is a good example of a situation where just scheduling your work differently across the graphics and compute queues can result in multi-ms gains.

This is just one example, but generally speaking, async compute is a great tool to get the most out of the GPU. Whenever it is possible to overlap some memory-intensive work with some compute-intensive tasks, there's opportunity for performance gains. We use async compute just the same way on both consoles. There are some hardware differences when it comes to the number of available queues, but with the way we're scheduling our compute tasks, this actually wasn't all that important.

On TSSAA:
Digital Foundry: Can you talk us through how the 8x TSSAA implementation works? Is it consistent between consoles and PC?

Tiago Sousa: I've always been a fan of amortising/decoupling frame costs. TSSAA is essentially doing that - it reconstructs an approximately 8x super-sampled image from data acquired over several frames, via a mix of image reprojection and couple heuristics for the accumulation buffer.

It has a relatively minimal runtime cost, plus the added benefit of temporal anti-aliasing to try to mitigate aliasing across frames (eg shading or geometry aliasing while moving camera slowly). It's mostly the same implementation between consoles and PC, differences being some GCN-specific optimisations for consoles and couple of minor simplifications.
 
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Tech Interview: Doom

Very nice interview, probably one of the very best DF articles in a while :)

On async compute:


On TSSAA:

I found this one interesting, most especially in terms of upcoming consoles. On the importance of resolution.

Digital Foundry: The scaler is highly effective on both PS4 and Xbox One. Can you give us your thoughts on the importance of resolution in general and its importance in terms of image quality?

Tiago Sousa: We don't use the native scaler from PS4/Xbox One, we do our own upsampling via a fairly optimal bicubic filter. It's also important to mention that the TSSAA implicitly takes into account the dynamic resolution scaling changes, mitigating aliasing occurring from resolution changes.

Resolution importance is a function of eye distance to display and display area - essentially the angular resolution - and to a degree also from the individual visual acuity. What that means is that the further away from your display, the higher the pixel density. After a certain distance/pixel density threshold you are essentially wasting performance that could be used to improve other things. In VR for example you have this tiny display on front of your face, pushing for higher pixel density still makes sense for dealing with things like geometry aliasing.

With console gameplay, where a player typically plays at a distance of two metres or more, and your display size is a common one (say 70" or so) it starts to become a performance waste relatively quickly, particularly if we are talking about 4K. If a developer does it the brute force way, you are essentially rasterising the same content, but literally 4x slower for not that much of a gain. Even for desktop rendering where users sit fairly close to the display, I can think of a myriad of approaches for decoupling resolution costs, than just brute force rendering.

The inference being that at least where iD is concerned, not everything will be rendered at 4k since there is little to no benefit to rendering everything at 4k. That doesn't mean the final rendered image won't be 4k, of course, just that in constructing that final image not everything has to be at 4k resolution. VR changes things drastically, however, due to how close the screen is to your eyes. The implication there is that it's likely that in the future rendering for VR will be significantly more costly than rendering non-VR 4K.

Regards,
SB
 
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Yep. I honestly have no idea why anyone thinks 8k will ever be necessary for the home.

Absolutely.

On the other hand, after finally trying out the current VR implementions first hand, 4k isn't going to be enough IMO. Current VR is only 1k basically (1k x 1k versus 2k x 1k for a 1080p screen) in terms of resolution available to the eye AND it takes up a massively larger display area meaning the angular resolution is absolutely pitiful when compared a 720p TV or even a 540p TV.

8k (8k x 8k and not 8k x 4k) might be enough, but I'm not even sure about that.

Regards,
SB
 
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I dont really agree with him though because playing maybe 12 feet away on my 55" 1080 TV, I noticed Doom looks pretty soft/blurry on XBO (IIRC DF says it's often running not much above 720P). It could definitely use a higher resolution.

I mean his overall point may be correct at some cutoff point, but Doom XBO seems to fall below it.

Halo 5 though, also dynamic res, usually looks sharp that I notice. I dont know if H5 is just typically settling at a higher res, using the technique better, or something else.

Tiago is a beast though, Doom looks great and we all know about Crysis.
 
I dont really agree with him though because playing maybe 12 feet away on my 55" 1080 TV, I noticed Doom looks pretty soft/blurry on XBO (IIRC DF says it's often running not much above 720P). It could definitely use a higher resolution.

Get a PS4.

:LOL:
 
As you increase resolution you really have to get closer (or get increasingly bigger screens) to notice the difference. As he said it's most probably a mix of ppi + distance from the screen. With more advanced methods of hitting 4k (temporal reconstruction, reprojection etc.) i think it's better to use the extra power on either framerate or effects or both rather than going full 4k frame buffer which both the Scorpio and especially Neo will struggle to hit on demanding titles. Doom on X1 might look soft but the IQ is still great, TSSAA is doing a marvelous job cleaning up the image and i hope we see more games using it :)
 
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